Dental caries and diseases

Dental caries is the most prevalent chronic disease

Classification

• Histopathologically-Enamal caries,Dentine caries,Cementum caries
• Clinically(according to location)-Pit and fissure,Smooth surface
• Clinial cause-Chronic,Acute

Smooth surface caries

• On approximal surface
• Early white spot lesion
• Then brown/black-due to pigmentation by dietary or bacterial products
• In SEM –cocci attached,small rounded dipressions and rough areas seen.
• Early lesions are conical in shape and 4 zones are seen.
• Translucent zone-due to demineralization
• Dark zone-due to remineralization
• Body of the lesion-due to greatest demineralization(subsurface decalcification)
• Surface zone-greater resistant to cariesactivity,30-40 micrometeres.relatively unaffected.
• Body-with water immersion with polarized microscope+bifringence-yellowcolour
• Surface zone-By a microradiograph
• Dark zone-with quinolne

Pit and fissure caries

• Cone shaped
• Base towards EDJ-because of this shape more dentinal tubules involved
• Occlusal surface caries(ground sec.-cz if demineralised 95% of inorganic part looses)
• Pit and fissure caries
• With steep walls and narrow bases easily cause caries
• In microradiograph lesion appear as radiolucent dark demineralised area
• In tooth-caries fissure is dark brown
• No loss of enamel surface continuity
• Morphology is intact
• Lesion can spread along DEJ
• Form cone shaped lesion in dentine
• With only small penetration of enamel is a common finding

Caries of dentine

• Caries of dentine(decalcified sec.-cz less inorganic part than enamel-so retain considerable amount after decalcification)
• After cavity forms in enamel carious process spreads along DEJ-rapid involvement of dentinal tubules-form- cone shaped lesion,apex towards pulp
• Dentine caries can occur as a result of exposure of dentine due to abrasion
• In ground section dentine show,
• pigmented zone
• Dark zone
• transparent zone-highly mineralized(radioopaque)deposition of ca2+salts in dentinal tubules to seal against bacteria.
• Decalcified section
• small amount on the surface of lesion
• involve deeper dentinal tubules-darkly stained
• initial decalcification of tubular walls-distention of tubules by placing microbes-focal areas of liquifraction necrosis form within dentinal tubules.those foci are filled with necrotic debris andd numerous microbes
• toward surface complete loss of dentine structure
• clefts parallel to contour lines of dentine(filled with necrotic debris + microbes)

Root caries

• After gingival recession
• Cementum is attached,readily decalcified
• Cementum softens beneth plaque over a wide area-cause soucer shaped cavity
• Underline dentine soon involved
• Cemnentum invade along sharpy’s fibers
• Infection spread belween lamelle along incremental lines-dentine split up and progressively destroy by demineralization and liquiofraction

Pulpitis

• Open –chronic hyperplastic pulpitis
• Closed –acute closed,chronic closed

Acute closed pulpitis

• Initial hyperemia limited to area underneath irritant.infiltration by inflammatory cells-destruction of odontoblasts & adjacent mesenchyme followed.
• Limited area of necrosis-form minute abscess localized by granulation tissue-inflammation spread until all pulp-entire pulp has been destroyed and replaced by inflammatory cells and dilated vessels

Chronic closed pulpitis

• Mononuclear cells infiltration
• More vigorus connective tissue reaction
• Small area of pulpal necrosis and pus formation is localized by well defined wall of granulation tissue-minute abscess form
• Reminder of pulp may appear normal
• Rarely inflammation is well localized beneth the exposure by-partial calcific barriersr benerth lesion(in X-ray dentine bridges) or reactionary dentine.
• Such changes likely to follow up pulp capping
• Calcific barriers usually poor-inflammation spread beneth but in successful reactionary entine-complete barrier-preserve rest of pulp.
• Open pulpitis
• Occationally pulp servives but chronically inflamed beneth wide exposure despite wide infection believed to be assiociate dwith open apices which allow adequate bld supply

Chronic Hyperplastic pulpitis(pulp polyp)

• Rarely despite of exposure and heavy infection.pulp not merely survive but proliferate through opening
• Clinically dusky red/pinkish soft nodule protruding in to cavity
• May tender/bleed on probing
• Histologically-odontoblasts survive,pulp replaced by granulation tissue,as mass grow out to cavity-it can become epithelialized and coverd by layer of well formed SSE
• Protects mass
• Subside

Branchial cyst

Branchial Cyst

· Arising from branchial arch remnants

· it has also been called lymphoepithelial cyst suggesting it's origin from cystic transformation of epithelium entrapted in cervical lymphnodes

· BC originated from 2nd arch->lateral aspect of upper neck near anterior border of sernocledomastoid muscle or at the mandibular angle

· Lesion->circumscribed fluctuent mass

· Young adults no sexual prediction

· Small ones canbe found in the floor of the mouth,Clinically resembles mucous retention cysts

· lined by stratified squamous epithelium

· Occationally columnar or cuboidal

· Cyst wall is composed of lymphoid tissue with scattered germinal centre surrounded by CT.

Anurysmal bone cyst

Aneurysmal bone Cyst

· Intra osseous lesions consist of blood filled cavernous spaces

· occur in some frequently in jaws and molar areaof younger individuals is the commenest site.

· rapidly expanding lesion

· X-ray multilocular radiolucency

· Thin fibrous CT wall and consist of many blood filled cavernous spaces

· False type of cyst.non epithelialized

Dermoid and epidermoid cyst

Dermoid Cyst

· Cyst of soft tissue

· Commnly occur sublingually

· Developmental abnormality or branchial arches/pharyngeal pouches

· Develop belween hyoid and jaw or many form immediatly beneththe tongue

· Filled with desquamated keratin(sometimes)giving a semisolid(salty) like consistancy.

· Have dermal appendages in the wall->give the name dermoid cyst

· Dermoid cyst is a form of cystic teratoma which is similar to structure of dermis

· Derived from embryonic germinal epithelium/acquired entrapted skin/mucosa

· Lined by stratified squamous epithelium and contain skin appendages such as sebaceous glands in CT wall

· Dermoid cysts in the head and neck region appearing symmetrical swellings in the floor of mouth

· There are presumed to derived by entrapment of epithelium remnents during closure of mandibular and hyoid branchial arches

· Sublingual type produce bulge in floor of mouth

· Submental type produce bulge in submental arch(dough-like on palpation)

Epidermoid Cyst

· Small epidermoid cysts may also be found in the tongue,soft palate,buccal mucosa and lips where they are considered to be acquired lesions resaulting from traumatic implantation of surface epithelium

Simple lesions without skin appandages are epidermoid cysts

Paradental cyst

Para Dental Cyst

· Occationally resault from inflammation around partially erupted teeth.

· Particularly mandibular 3rd molars

· Affects males predominantly 20-25yrs

· Affected tooth is vital but show pericoronitis

Histopathologically

· Resembles radicular cyst

· But more inflammatory infiltration in wall.